Handed over to debt collectors without communication

We had a call from Debt collectors informing us that our Woolworths account is in arrears and handed over. We had no calls or emails ever of any amount outstanding amount and had made no purchases. We informed them that we will be able to pay on the 26 when we receive our salaries. This was agreed to. Now we received a letter that we must pay today. We will pay on the 26 and then you can close the account. We will not do business with ********* companies.